Grow Your Way to Less Carbon

Posted by Carl McDaniel
Carl McDaniel
Carl McDaniel is a university research scientist who retired to Oberlin several
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on July 29, 2013 in Energy Matters

Why have a vegetable garden?

Oberlin Community Service’s June networking lunch was crowded—perhaps 50 people were there. A panel of nine represented the diversity of local food and gardening projects in Oberlin from school to neighborhood gardens.

None of these existed two decades ago;  most are just a few years old. Oberlin’s farmers market was a handful of booths when we arrived in 2008. And it was only during the growing season. Today it’s a year-round Saturday morning social event and fills a good portion of the City Hall parking lot.

A recent survey found that over 40% of Oberlin residents grow food in a portion of their yards, some in the front yard. Oberlin reflects the recent national movement back to garden fresh food. My father had a victory garden in the 1940s, but it was for the war effort. The present movement has different motivations.

A vegetable garden provides delicious healthy food. Eating just-picked green beans, lettuce, tomatoes, and even zucchini is a sensual delight. When planting, weeding, and harvesting, you are out-of-doors getting exercise. The garden connects you to your food and the natural world. You save money, too. Equally important you have the satisfaction of growing a portion of your food.

Most of these positive attributes of vegetable gardening were considered or implied by the OCS panel. Unintentionally, they let slip by one very important benefit; growing your own food reduces the use of fossil fuels.

Industrially produced food requires substantial energy inputs. Experts estimate that the average number of Calories of fossil fuel used in the United States to put ONE Calorie of food on your table is 10 Calories. That’s right—each Calorie of conventionally-raised food you eat took 10 times the amount of energy to produce and deliver it to your table. Is this a sensible or sustainable food system?  

We’ve had a garden for many years because we love freshly harvested vegetables as well as root crops and squash that provide “garden-fresh” produce through the winter. More recently we’ve realized our garden reduces our contribution to climate change.

Very little energy is used in raising garden produce, perhaps one Calorie to put a Calorie of food on the table, thereby off-setting nine Calories of fossil fuel. Because Calories are only used as a food energy unit, the offset would be 36 British Thermal Units (BTUs) where one Calorie equals four BTUs. Based on the mix of crops grown in our garden last year—potatoes, sweet potatoes, butternut squash, broccoli, lettuce, okra, carrots, tomatoes, beets, egg plant, peppers, green beans, soybeans, onions, Swiss chard, yellow and zucchini squash—each pound harvested off-set about 750 BTU of fossil fuel.

Based on this estimate and the size of our garden, you can offset about 1.5 million BTUs of fossil fuel with a modest size garden (30 feet by 20 feet). For comparison, the average U.S. house runs annually on about 100 million BTUs of purchased energy. Alternatively 1.5 million BTUs is the energy in 12 gallons of gasoline—a lot of energy.

Enjoy the delicious vegetables from your or a local garden! As you savor the taste and texture, know too that you are reducing your carbon footprint.

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Carl McDaniel is a university research scientist who retired to Oberlin several years ago. He and his wife built Trail Magic, their residence, which has no energy bill and runs on free sunshine.


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